Apparatus for management and remote control of electrical characteristics of each wire pairs connected to a telephone exchange and to a distribution frame

ABSTRACT

An apparatus for the management and the remote and/or automatic control of electric characteristics and signal transmissivity of the metallic line pairs connected to a telephone exchange (C), comprising measurement means and means able to connect said measurement means to the single line pairs connected to the telephone exchange and then to all of the lines of a distribution whether they are active or redundant.

The present invention relates the field of the dial telephone systemsand particularly an apparatus for monitoring electric characteristicsand signal transmissivity in line pairs (usually of copper or aluminium)connected to exchanges.

With the liberalization of the telecommunication systems, the majorTelephone Companies, once holder of the monopoly, have been compelled todrastically reduce the cost in order to be competitive with thecompetition of the new Telecommunication Managers.

The prevailing reason of this is the unbalance situation between, on oneside, the new Managers having only to pay the rent for telephonenetworks and services, and, on the other side, the Telephone Companies,once holder of the monopoly, that are burdened with the cost ofoperation and maintenance of the access network requiring a significantamount of human resources because of the lack of automatic controlsystem, thus generating an important item in the budget of suchcompanies.

However, the cutting of the investment regarding operation andmaintenance has the fated consequence of the network quality degradationas far as the quality of the signal and the data transmission rate isconcerned.

Regarding the situation of the Company Telecom Italia, the cutting ofthe budget in recent years have increased the failure rate of thenetwork (number of failures per 100 km cable in a year) from 5-6% of1997 to 13-14% of today.

Such a situation is further emphasized by the wide band services (ADSL)which need better electric characteristics of the network to operatecorrectly, thus compelling the Manager to a preventive, quick, effectiveintervention for improving the efficiency of the lines and to solve theproblems on pain of the commercial failure.

On the other side, no Telephone Company can be burdened with the cost ofsuch activity if the latter is carried out by the traditionalintervention of technicians.

Therefore, it is self-evident that with the coming of new digitalwideband services, in order to achieve a good reliability and quality ofthe access network with successfully commercial consequences andcustomer satisfaction as well, it is necessary to perform a newmanagement of the network based on the preventive control of the linesaccording to the technical requirements of the new services that cannotabsolutely be-implemented both technically and economically by thetraditional modes of operation.

In other words the old operation methods performing an intervention onthe network only following a customer's failure notice are extremelyburdensome with respect to the new scenery and cause troubles to thecustomer.

In order to overcome such problems, worldwide telecommunicationequipment manufacturing companies such as Teradyne, Sunrise, Turnstone,etc., have provided remote controlled systems for line testing andaccess network failure detection tested by Telecom Italia, BritishTelecom, Colt, Cable & Wireless, etc.

The results have been deemed by the Managers not satisfactory because ofthe lack of reliability of the measurements carried out by such systems.For this reason, a system able to solve this crucial problem is stillbeing developed all over Europe and particularly by British Telecom thatfirst has been looking for a system able not only to test thecharacteristics of a line but also to detect automatically networkfailures. The main object of the present invention is to provide anapparatus able to carry out automatically and remotely the monitoring ofthe dial telephone systems (e.g. copper or aluminium) to test electriccharacteristics and signal transmissivity.

A second object of the invention is to provide means for testing thequality of the lines as far the electric characteristics and the signaltransmission rate is concerned, which means does not require anyre-wiring of the line pairs or modification of the exchange apparatus towhich such line pairs are connected.

A third object of the invention is to provide an apparatus able to testboth the line pairs connected to customers and the redundant line pairsand those rented by other managers independent of that they are audiolines, digital lines (ISDN) or wideband lines (ADSL).

This has been accomplished according to the present invention byproviding an apparatus which can be remote controlled in any exchange,comprising measurement means and means for the connection of suchmeasurement means to the single line pairs connected to the exchange aswell as to all of the lines connected thereto whether they are active orredundant.

A better understanding of the invention will result from the followingdescription with reference to the accompanying drawings of the knownexchanges and two preferred embodiments thereof shown only by way of anot limiting example.

In the drawings:

FIG. 1 is a diagram showing an exchange of the known type to which theaccess network is connected;

FIG. 2, similar to the preceding figure, shows the installation of ameasurement unit of the know type in the exchange that is connected tothe autoswitch of the exchange according to already tested techniques;

FIG. 3 shows schematically an exchange of the known type in which theapparatus according to the present invention is installed;

FIG. 4 is a block diagram of the apparatus according to the invention;

FIG. 5 is an exemplifying wiring diagram of a first embodiment of aninterface device by which the measurement means is connected to thesingle line pairs connected to the exchange; and

FIG. 6, similar to the preceding figure, shows a second simplifiedembodiment of an interface device according to the invention.

In order to illustrate in a more detailed way the scenery to which theinvention is related, reference is made first to FIGS. 1 and 2.

From the diagram of FIG. 1 it appears that all of the lines connected toa customer are conveyed to a permutator P. The audio service dedicatedlines F are connected directly to autoswitch AC, while ADSL (wideband)lines pass before being connected to the autoswitch through a deviceDSLAM of the known type that provides the wideband service by separatingthe same from the audio signal by a pots filter PF of the known type.

Control and measurement systems developed so far provide, as shown inthe diagram of FIG. 2, the installation of a remote controlledmeasurement device in the exchange which is able to measure and tocontrol the lines directly connected to the autoswitch by means of aknown function of the autoswitch AC.

Although such a solution has the advantage of being brought about byonly connecting a measurement unit to autoswitch AC, it has thefollowing limits which has made it unsuccessful:

-   -   1. The quality of the qualification measurements is insufficient        because of the limits caused by the transit of the line through        autoswitch AC;    -   2. In case of an ADSL line, once the preventive qualification        measurements are carried out and the service is activated, the        line cannot be tested any longer by such system because of the        already described separation filter PS which is connected        between autoswitch AC and the line;    -   3. As the access network is designed with a redundancy of about        40% (every 100 lines from exchange C, 60 lines connect customers        and 40 lines are only connected to permutator P and left as        spare), all of the spare lines are not managed by the        measurement system described above as they are not connected to        the autoswitch;    -   4. The same limit of the preceding item is valid for all of the        lines rented to other operators (unbundling).

Modern exchanges are usually provided, as an alternative to thepermutator P, with a switch matrix access, however, the use of suchmatrixes in the already existing exchanges in which the lines areconnected to a permutator cannot be applied in praxis due to the highcost involved by such operation.

The diagram of FIG. 3 shows the solution according to the presentinvention, characterized by the installation of a remote controlled testand measurement device 10 at the exchange C which includes measurementapparatus connected to suitable devices 20 installed in the permutator Pwhich are able to connect to all of the lines arriving to suchpermutator and then to all of the line pairs from the exchange which areeither connected to a customer (rented) or redundant.

Such a solution allows the connecting device 20 to be connected to allof the lines and the above-mentioned limits of the known systems to beovercomes thus ensuring a complete, economic control of the accessnetwork because of the monitoring of all lines.

For example, the lines for any service, included the wideband service,can be qualified completely and advantageously both from the technicaland economical point of view as the intervention of technicians in situis not required. In case of failure, the system is able to detectremotely the point of failure, thus allowing the repair and the on linecontrol of the quality of such repair. In addition, the invention isable both to detect the degradation of the lines and to locate anyfailure by a suitable software for monitoring continuously the lines,all of this being executed automatically with evident cost savings aswell as improvements in the organization and the image to customers.

It is advisable now to disclose the measurement and control apparatus 10and the relative connecting devices 20 according to the invention, thatare installed in the strips connecting the line pairs (externaltelephone network) to the permutator P and are controlled directly bythe measurement apparatus disclosed.

With particular reference to FIGS. 3 and 4, the present inventionincludes essentially:

-   -   a measurement and control apparatus 10;    -   a plurality of connecting devices 20 with the single connecting        strips SA;    -   a number of interface devices M, one for each column of        permutator P, which connect the connecting devices 20 to the        measurement and control apparatus 10.

More specifically the measurement and control apparatus 10 includes:means for the communication with the remote control centre; means forthe measurement of the electric quantities and the transmission signalsin the line pairs connected to exchange C; means for storing, processingand controlling signals received from/transmitted to the remote controlcentre; power supply means; a driver controlling the communicationbetween the single line pair to be tested and the measurement means bydriving the interface devices M and connecting devices 20.

It should be noted that each interface device M installed at the top ofthe respective column of the permutator P (or in another suitableposition) is able to connect the selected line pair(s) to themeasurement means according to the control signals received from suchprocessing and control means in order to connect the connecting device20 of each column to the measurement and control apparatus 10.

Each interface device M is connected to the other interface apparatusand the measurement and control apparatus 10 by two measurement linepairs T1 and T2 and a common control bus S.

In the preferred embodiment disclosed, each of them is provided with aserial gate by which the switching of the line pairs to the testterminal of line pairs T1 and T2 is controlled.

Furthermore, such interface devices M are able to recognize a tonetransmitted from the external network or the exchange to test again theline pairs and to re-arrange the numbers of the exchange to thepermutator P.

Each connecting device 20 shown schematically in FIG. 5 is connected tothe interface device M corresponding to its column by two measurementline pairs T1-T2 and a control bus S.

Referring to the latter figure, it should be noted that according to apeculiar feature of the invention such connecting device 20 is able toconnect, to section, and to transfer each line pair connected to thepermutation strips, thus making them available to the above-mentionedmeasurement means.

According to the invention, this is advantageously carried out withoutthe need of modifying in any way the existing wiring of permutator P.Only the first two line pairs N1, N2 and the n-th line pairs ND, NP areshown in the figure for the sake of clarity.

Each connecting-sectioning-transferring device 20 which is characterizedby a low parasitic capacitance acts as a multiple sectioning plug andreproduces the exact geographic allocation of the sectioning points ofthe several existing vertical or horizontal connecting strips both onthe side interfacing the existing strip SA and the side of theoperators. The installation requires only the insertion of the singleconnecting devices or modules 20 into the respective connecting stripsSA of the line pairs of the permutator P.

Each connecting-sectioning-transferring device 20 consists of a bodywhich includes by way of a not limiting example two shells forming thetwo operating sections.

The “male” section interfacing connecting strips SA of permutator P isprovided with the sectioning plugs 4 that once inserted into thecorresponding sectioning points 5 establish both the mechanicalconnection between the existing strip SA and module 20 and the galvanicconnection of each single connected line pair without the need ofmodifying the existing wiring.

Once the connecting-sectioning-transferring device 20 is connected, eachgeneric line pair connected to, the network side “ar, br” of thesectioning point 5 of strip SA of permutator P is sectioned andgalvanically interrupted by the contacts of the sectioning plug 4.According to the invention, two on-line relays are provided for eachline pair: a first sectioning relay 3 connected in series, and a secondmonitoring “sniffer” relay 2 connected in parallel.

The rest contacts of sectioning relay 3 ensure the normal continuity ofthe line pair before the connection of device 20, thus making such linepair available to the central side “ac, bc” of the sectioning point 5through the rest contacts of the corresponding sectioning points 6 ofthe “female” section of device 20 which further put again in operationthe strip in case the same line pair should be sectioned locally.

Suitably coded control signals relative to the line pair to be testedand the type of test to be executed are fed to an actuator 1 through busS.

Accordingly, actuator 1 activates one of the sectioning relays 3 ormonitoring relays 2 according to whether an intrusive or non-intrusivemeasurement has to be carried out, and gives back a signal indicatingthe established connection.

In case of an intrusive measurement, the action of relay 3 provides forsectioning a line pair so that the side of the network is made availableon the test line pairs T1 if it is odd, and T2 if it is even.

In case of a non-intrusive measurement, relay 2 puts test line pair T2,if it is odd, or T1, if it is even, in parallel with the line to betested.

The simultaneous action of the two sectioning relays 3, one for the evenline pairs, the other for the odd line pairs, allows the network side ofthe two line pairs to be connected simultaneously to the measurementunit.

The simultaneous action of the two line relays 2 and 3 of a single linepair allows the network side and the exchange side of the tested linepair to be made available alternatively according to whether theselected line pair is odd or even.

As already mentioned, each connecting-sectioning-transferring module 20is connected to other modules and the measurement and control apparatus10 by only two test-line pairs T1-T2 and a common bus S.

Advantageously, according to the invention, the relevant peculiarity ofwhich is to avoid the need of wiring again each single line pairsconnected to permutator P, thus also avoiding to twist the existinginstallation, it is possible to test all of the line pairs, thusoptimizing the use of the high-technology apparatus disclosed hereinwhich is able to carry out measurements without any need of providingnew services and to provide a measurement and test system characterizedby a great simplicity, cheapness, and installation velocity.

At last, it should be appreciated that the present invention allowsqualification measurements, certifications, maintenance and failuredetection to be carried out all over a network of a determined areadirectly from a control centre as well as any degradation of the linepairs and any failure to be automatically detected by a suitablesoftware.

A second embodiment of the invention has connecting device 20′simplified with respect to those described so far. In fact, in thissecond embodiment each connecting device 20′ is provided with only twoline pairs to carry out measurements and to be controlled, only one testline pair T and a bus S.

As it has been described in the preceding embodiment, once theconnecting-sectioning-transferring module 20′ is connected, each genericline pair connected to the network side “lr” of the sectioning point 5of strip SA of permutator P is sectioned and galvanically interrupted bythe contacts of the sectioning plug 4.

According to the invention, two on line relays are provided for eachline pair: a first sectioning relay 3 connected in series, and a secondmonitoring “sniffer” relay 2 connected in parallel.

The rest contacts of sectioning relay 3 ensure the normal continuity ofthe line pair before the connection of device 20′, thus making such linepair available to the central side “Ic” of the sectioning point 5through the rest contacts of the corresponding sectioning points 6 ofthe “female” section of device 20′ which further put again in operationthe strip in case the same line pair should be sectioned.

Suitably coded control signals relative to the line pair to be testedand the type of test to be executed are fed to an actuator 1 through busS.

Accordingly, actuator 1 activates one of the sectioning relays 3 ormonitoring relays 2 according to whether an intrusive or non-intrusivemeasurement has to be carried out, and gives back a signal indicatingthe established connection.

In case of an intrusive measurement, the action of relay 3 provides forsectioning a line pair so that the side of the network is made availableon the test line pairs T.

In case of a non-intrusive measurement, relay 2 puts test line pair T inparallel with the line to be tested.

As already mentioned, each connecting-sectioning-transferring module 20′is connected to other modules and the measurement and control apparatus10 by only one test line pair T and a common bus S.

The present invention has been described and illustrated according totwo preferred embodiments thereof, however, it should be understoodanyone skilled in the art can make technically and/or functionallyequivalent modifications and/or replacements without departing from thescope of the present industrial invention.

1. An apparatus for the management and the remote and/or automaticcontrol of electric characteristics and signal transmissivity in themetallic line pairs connected to a telephone exchange, the apparatuscomprising: measurement means; and means for selectively connecting saidmeasurement means to single line pairs connected to the telephoneexchange and to all line pairs whether they are active or redundant. 2.The apparatus of claim 1, further comprising a measurement apparatusconnected to at least one connecting device installed in at least apermutator of the telephone exchange configured to selectively connectto all of the lines arriving to the permutator and to all of the linepairs from the telephone exchange which are either connected to acustomer (rented) or redundant, said apparatus being configured to beinstalled in the telephone exchange and to be remote controlled viacable, or via ethernet, or locally controlled.
 3. The apparatus of claim2 wherein a connection of the at least one connecting device to all ofthe pairs is configured to allow the apparatus to detect remotely apoint of failure and to perform an on line test of the quality of arepair of the detected point of failure.
 4. The apparatus of claim 1comprising: a measurement and control apparatus; a plurality ofconnecting devices having single connecting strips a number of interfacedevices, one for each column of permutator, which connect the pluralityof connecting devices to the measurement and control apparatus.
 5. Theapparatus of claim 4, wherein the measurement and control apparatusincludes: means for communication with a remote control centre; meansfor measurement of electric quantities and transmission signals of linepairs connected to the telephone exchange; means for storing, processingand controlling signals received from/transmitted to the remote controlcentre; power supply means; a driver controlling communication between asingle line pair to be tested and the measurement means by driving theinterface devices and connecting devices.
 6. The apparatus of claim 5,wherein each interface device is installed at its respective column ofthe permutator to connect the plurality of connecting devices of eachcolumn to the measurement and control apparatus and is configured toconnect a selected one of the line pairs to the measurement means basedon control signals received from the means for storing processing andcontrolling signals.
 7. The apparatus of claim 6, wherein each interfacedevice is connected to other interface apparatus and the measurement andcontrol apparatus by one or more measurement line pairs and a commoncontrol bus.
 8. The apparatus of claim 7, wherein each interface deviceincludes a serial gate by which the switching of the line pairs to atest terminal one of the measurement line pairs or a test terminal ofanother of the (line pairs is controlled.
 9. The apparatus of claim 8,wherein the interface devices are configured to recognize a tonetransmitted from an external network or the telephone exchange to testagain at least one of the line pairs and to re-arrange numbers of thetelephone exchange to the permutator.
 10. The apparatus of claim 9,wherein each connecting device is connected to the interface devicecorresponding to its column by the one or more measurement line pairsand the control bus.
 11. The apparatus of claim 10, wherein theplurality of connecting devices are configured to connect, to section,and to transfer each line pair connected to the single connecting stripto make them available to the measurement means, at least one of theconnecting devices—being configured to act as a multiple sectioning plugand reproducing an exact geographic allocation of sectioning points of aplurality of existing vertical or horizontal connecting strips both on aside interfacing the connecting strip and an operator side.
 12. Theapparatus, of claim 11, wherein each connecting device includes a bodywhich includes two shells forming “male” and “female” sections,respectively, the female of which reproduces sectioning points in whichthe male section is inserted.
 13. The apparatus of claim 12, wherein the“male” section of the connecting device for interfacing the connectingstrip of the permutator is provided with sectioning plugs that onceinserted into the corresponding sectioning points establish both amechanical connection between the connecting strip and the connectingdevice and a galvanic connection of each single connected line pairwithout modifying existing wiring, each line pair connected to a networkside of the sectioning point of the connecting strip of the permutatorbeing sectioned and galvanically interrupted by contacts of thesectioning plug.
 14. The apparatus of claim 13, wherein the connectingdevice includes two on-line relays for each line pair: a firstsectioning relay connected in series, and a second monitoring “sniffer”relay connected in parallel.
 15. The apparatus of claim 14, whereincontacts of the sectioning relay provide a same normal continuity of theline pair as before the connection of the connecting device to make suchline pair available to a central side of the sectioning point throughcontacts of corresponding sectioning points of the “female” section ofthe connecting device which further put again into operation the stripin case the same line pair should be locally sectioned.
 16. Theapparatus of claim 15 wherein the connecting device includes an actuatormodule which, responsive to coded control signals relative to a linepair to be tested and a type of test to be executed through the commoncontrol bus, activates one of the line relays present in the deviceaccording to whether an intrusive or non-intrusive measurement is to becarried out, and gives back a signal indicating an establishedconnection.
 17. The apparatus of claim 16, wherein, in order to carryout an intrusive measurement, the of first relay provides for sectioninga line pair so that the network side is made available on the test linepair or on the first test line pairs, if it is odd, and on the secondtest line pairs, if it is even.
 18. The apparatus of claim 16, wherein,in order to carry out a non-intrusive measurement, the second relay putsthe test line pair or the second test line pairs, if it is odd, or thefirst test line pairs, if it is even, in parallel with a line to betested.
 19. The apparatus of claim 17, wherein simultaneous action oftwo of the first relays, one for even line pairs, the other for odd linepairs, allows the network side of the two line pairs to be connectedsimultaneously to the measurement unit, while simultaneous action of thefirst and second relays of a single line pair allows the network sideand the exchange side of the tested line pair or the first and secondtest line pairs to be made available alternatively according to whetherthe selected line pair is odd or even.